xref: /linux/drivers/usb/misc/iowarrior.c (revision c537b994505099b7197e7d3125b942ecbcc51eb6)
1 /*
2  *  Native support for the I/O-Warrior USB devices
3  *
4  *  Copyright (c) 2003-2005  Code Mercenaries GmbH
5  *  written by Christian Lucht <lucht@codemercs.com>
6  *
7  *  based on
8 
9  *  usb-skeleton.c by Greg Kroah-Hartman  <greg@kroah.com>
10  *  brlvger.c by Stephane Dalton  <sdalton@videotron.ca>
11  *           and St�hane Doyon   <s.doyon@videotron.ca>
12  *
13  *  Released under the GPLv2.
14  */
15 
16 #include <linux/module.h>
17 #include <linux/usb.h>
18 #include <linux/init.h>
19 #include <linux/slab.h>
20 #include <linux/sched.h>
21 #include <linux/poll.h>
22 #include <linux/version.h>
23 #include <linux/usb/iowarrior.h>
24 
25 /* Version Information */
26 #define DRIVER_VERSION "v0.4.0"
27 #define DRIVER_AUTHOR "Christian Lucht <lucht@codemercs.com>"
28 #define DRIVER_DESC "USB IO-Warrior driver (Linux 2.6.x)"
29 
30 #define USB_VENDOR_ID_CODEMERCS		1984
31 /* low speed iowarrior */
32 #define USB_DEVICE_ID_CODEMERCS_IOW40	0x1500
33 #define USB_DEVICE_ID_CODEMERCS_IOW24	0x1501
34 #define USB_DEVICE_ID_CODEMERCS_IOWPV1	0x1511
35 #define USB_DEVICE_ID_CODEMERCS_IOWPV2	0x1512
36 /* full speed iowarrior */
37 #define USB_DEVICE_ID_CODEMERCS_IOW56	0x1503
38 
39 /* Get a minor range for your devices from the usb maintainer */
40 #ifdef CONFIG_USB_DYNAMIC_MINORS
41 #define IOWARRIOR_MINOR_BASE	0
42 #else
43 #define IOWARRIOR_MINOR_BASE	208	// SKELETON_MINOR_BASE 192 + 16, not offical yet
44 #endif
45 
46 /* interrupt input queue size */
47 #define MAX_INTERRUPT_BUFFER 16
48 /*
49    maximum number of urbs that are submitted for writes at the same time,
50    this applies to the IOWarrior56 only!
51    IOWarrior24 and IOWarrior40 use synchronous usb_control_msg calls.
52 */
53 #define MAX_WRITES_IN_FLIGHT 4
54 
55 /* Use our own dbg macro */
56 #undef dbg
57 #define dbg( format, arg... ) do { if( debug ) printk( KERN_DEBUG __FILE__ ": " format "\n" , ## arg ); } while ( 0 )
58 
59 MODULE_AUTHOR(DRIVER_AUTHOR);
60 MODULE_DESCRIPTION(DRIVER_DESC);
61 MODULE_LICENSE("GPL");
62 
63 /* Module parameters */
64 static int debug = 0;
65 module_param(debug, bool, 0644);
66 MODULE_PARM_DESC(debug, "debug=1 enables debugging messages");
67 
68 static struct usb_driver iowarrior_driver;
69 
70 /*--------------*/
71 /*     data     */
72 /*--------------*/
73 
74 /* Structure to hold all of our device specific stuff */
75 struct iowarrior {
76 	struct mutex mutex;			/* locks this structure */
77 	struct usb_device *udev;		/* save off the usb device pointer */
78 	struct usb_interface *interface;	/* the interface for this device */
79 	unsigned char minor;			/* the starting minor number for this device */
80 	struct usb_endpoint_descriptor *int_out_endpoint;	/* endpoint for reading (needed for IOW56 only) */
81 	struct usb_endpoint_descriptor *int_in_endpoint;	/* endpoint for reading */
82 	struct urb *int_in_urb;		/* the urb for reading data */
83 	unsigned char *int_in_buffer;	/* buffer for data to be read */
84 	unsigned char serial_number;	/* to detect lost packages */
85 	unsigned char *read_queue;	/* size is MAX_INTERRUPT_BUFFER * packet size */
86 	wait_queue_head_t read_wait;
87 	wait_queue_head_t write_wait;	/* wait-queue for writing to the device */
88 	atomic_t write_busy;		/* number of write-urbs submitted */
89 	atomic_t read_idx;
90 	atomic_t intr_idx;
91 	spinlock_t intr_idx_lock;	/* protects intr_idx */
92 	atomic_t overflow_flag;		/* signals an index 'rollover' */
93 	int present;			/* this is 1 as long as the device is connected */
94 	int opened;			/* this is 1 if the device is currently open */
95 	char chip_serial[9];		/* the serial number string of the chip connected */
96 	int report_size;		/* number of bytes in a report */
97 	u16 product_id;
98 };
99 
100 /*--------------*/
101 /*    globals   */
102 /*--------------*/
103 /* prevent races between open() and disconnect() */
104 static DECLARE_MUTEX(disconnect_sem);
105 
106 /*
107  *  USB spec identifies 5 second timeouts.
108  */
109 #define GET_TIMEOUT 5
110 #define USB_REQ_GET_REPORT  0x01
111 //#if 0
112 static int usb_get_report(struct usb_device *dev,
113 			  struct usb_host_interface *inter, unsigned char type,
114 			  unsigned char id, void *buf, int size)
115 {
116 	return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
117 			       USB_REQ_GET_REPORT,
118 			       USB_DIR_IN | USB_TYPE_CLASS |
119 			       USB_RECIP_INTERFACE, (type << 8) + id,
120 			       inter->desc.bInterfaceNumber, buf, size,
121 			       GET_TIMEOUT);
122 }
123 //#endif
124 
125 #define USB_REQ_SET_REPORT 0x09
126 
127 static int usb_set_report(struct usb_interface *intf, unsigned char type,
128 			  unsigned char id, void *buf, int size)
129 {
130 	return usb_control_msg(interface_to_usbdev(intf),
131 			       usb_sndctrlpipe(interface_to_usbdev(intf), 0),
132 			       USB_REQ_SET_REPORT,
133 			       USB_TYPE_CLASS | USB_RECIP_INTERFACE,
134 			       (type << 8) + id,
135 			       intf->cur_altsetting->desc.bInterfaceNumber, buf,
136 			       size, 1);
137 }
138 
139 /*---------------------*/
140 /* driver registration */
141 /*---------------------*/
142 /* table of devices that work with this driver */
143 static struct usb_device_id iowarrior_ids[] = {
144 	{USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOW40)},
145 	{USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOW24)},
146 	{USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOWPV1)},
147 	{USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOWPV2)},
148 	{USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOW56)},
149 	{}			/* Terminating entry */
150 };
151 MODULE_DEVICE_TABLE(usb, iowarrior_ids);
152 
153 /*
154  * USB callback handler for reading data
155  */
156 static void iowarrior_callback(struct urb *urb)
157 {
158 	struct iowarrior *dev = (struct iowarrior *)urb->context;
159 	int intr_idx;
160 	int read_idx;
161 	int aux_idx;
162 	int offset;
163 	int status;
164 
165 	switch (urb->status) {
166 	case 0:
167 		/* success */
168 		break;
169 	case -ECONNRESET:
170 	case -ENOENT:
171 	case -ESHUTDOWN:
172 		return;
173 	default:
174 		goto exit;
175 	}
176 
177 	spin_lock(&dev->intr_idx_lock);
178 	intr_idx = atomic_read(&dev->intr_idx);
179 	/* aux_idx become previous intr_idx */
180 	aux_idx = (intr_idx == 0) ? (MAX_INTERRUPT_BUFFER - 1) : (intr_idx - 1);
181 	read_idx = atomic_read(&dev->read_idx);
182 
183 	/* queue is not empty and it's interface 0 */
184 	if ((intr_idx != read_idx)
185 	    && (dev->interface->cur_altsetting->desc.bInterfaceNumber == 0)) {
186 		/* + 1 for serial number */
187 		offset = aux_idx * (dev->report_size + 1);
188 		if (!memcmp
189 		    (dev->read_queue + offset, urb->transfer_buffer,
190 		     dev->report_size)) {
191 			/* equal values on interface 0 will be ignored */
192 			spin_unlock(&dev->intr_idx_lock);
193 			goto exit;
194 		}
195 	}
196 
197 	/* aux_idx become next intr_idx */
198 	aux_idx = (intr_idx == (MAX_INTERRUPT_BUFFER - 1)) ? 0 : (intr_idx + 1);
199 	if (read_idx == aux_idx) {
200 		/* queue full, dropping oldest input */
201 		read_idx = (++read_idx == MAX_INTERRUPT_BUFFER) ? 0 : read_idx;
202 		atomic_set(&dev->read_idx, read_idx);
203 		atomic_set(&dev->overflow_flag, 1);
204 	}
205 
206 	/* +1 for serial number */
207 	offset = intr_idx * (dev->report_size + 1);
208 	memcpy(dev->read_queue + offset, urb->transfer_buffer,
209 	       dev->report_size);
210 	*(dev->read_queue + offset + (dev->report_size)) = dev->serial_number++;
211 
212 	atomic_set(&dev->intr_idx, aux_idx);
213 	spin_unlock(&dev->intr_idx_lock);
214 	/* tell the blocking read about the new data */
215 	wake_up_interruptible(&dev->read_wait);
216 
217 exit:
218 	status = usb_submit_urb(urb, GFP_ATOMIC);
219 	if (status)
220 		dev_err(&dev->interface->dev, "%s - usb_submit_urb failed with result %d",
221 			__FUNCTION__, status);
222 
223 }
224 
225 /*
226  * USB Callback handler for write-ops
227  */
228 static void iowarrior_write_callback(struct urb *urb)
229 {
230 	struct iowarrior *dev;
231 	dev = (struct iowarrior *)urb->context;
232 	/* sync/async unlink faults aren't errors */
233 	if (urb->status &&
234 	    !(urb->status == -ENOENT ||
235 	      urb->status == -ECONNRESET || urb->status == -ESHUTDOWN)) {
236 		dbg("%s - nonzero write bulk status received: %d",
237 		    __func__, urb->status);
238 	}
239 	/* free up our allocated buffer */
240 	usb_buffer_free(urb->dev, urb->transfer_buffer_length,
241 			urb->transfer_buffer, urb->transfer_dma);
242 	/* tell a waiting writer the interrupt-out-pipe is available again */
243 	atomic_dec(&dev->write_busy);
244 	wake_up_interruptible(&dev->write_wait);
245 }
246 
247 /**
248  *	iowarrior_delete
249  */
250 static inline void iowarrior_delete(struct iowarrior *dev)
251 {
252 	dbg("%s - minor %d", __func__, dev->minor);
253 	kfree(dev->int_in_buffer);
254 	usb_free_urb(dev->int_in_urb);
255 	kfree(dev->read_queue);
256 	kfree(dev);
257 }
258 
259 /*---------------------*/
260 /* fops implementation */
261 /*---------------------*/
262 
263 static int read_index(struct iowarrior *dev)
264 {
265 	int intr_idx, read_idx;
266 
267 	read_idx = atomic_read(&dev->read_idx);
268 	intr_idx = atomic_read(&dev->intr_idx);
269 
270 	return (read_idx == intr_idx ? -1 : read_idx);
271 }
272 
273 /**
274  *  iowarrior_read
275  */
276 static ssize_t iowarrior_read(struct file *file, char __user *buffer,
277 			      size_t count, loff_t *ppos)
278 {
279 	struct iowarrior *dev;
280 	int read_idx;
281 	int offset;
282 
283 	dev = (struct iowarrior *)file->private_data;
284 
285 	/* verify that the device wasn't unplugged */
286 	if (dev == NULL || !dev->present)
287 		return -ENODEV;
288 
289 	dbg("%s - minor %d, count = %zd", __func__, dev->minor, count);
290 
291 	/* read count must be packet size (+ time stamp) */
292 	if ((count != dev->report_size)
293 	    && (count != (dev->report_size + 1)))
294 		return -EINVAL;
295 
296 	/* repeat until no buffer overrun in callback handler occur */
297 	do {
298 		atomic_set(&dev->overflow_flag, 0);
299 		if ((read_idx = read_index(dev)) == -1) {
300 			/* queue emty */
301 			if (file->f_flags & O_NONBLOCK)
302 				return -EAGAIN;
303 			else {
304 				//next line will return when there is either new data, or the device is unplugged
305 				int r = wait_event_interruptible(dev->read_wait,
306 								 (!dev->present
307 								  || (read_idx =
308 								      read_index
309 								      (dev)) !=
310 								  -1));
311 				if (r) {
312 					//we were interrupted by a signal
313 					return -ERESTART;
314 				}
315 				if (!dev->present) {
316 					//The device was unplugged
317 					return -ENODEV;
318 				}
319 				if (read_idx == -1) {
320 					// Can this happen ???
321 					return 0;
322 				}
323 			}
324 		}
325 
326 		offset = read_idx * (dev->report_size + 1);
327 		if (copy_to_user(buffer, dev->read_queue + offset, count)) {
328 			return -EFAULT;
329 		}
330 	} while (atomic_read(&dev->overflow_flag));
331 
332 	read_idx = ++read_idx == MAX_INTERRUPT_BUFFER ? 0 : read_idx;
333 	atomic_set(&dev->read_idx, read_idx);
334 	return count;
335 }
336 
337 /*
338  * iowarrior_write
339  */
340 static ssize_t iowarrior_write(struct file *file,
341 			       const char __user *user_buffer,
342 			       size_t count, loff_t *ppos)
343 {
344 	struct iowarrior *dev;
345 	int retval = 0;
346 	char *buf = NULL;	/* for IOW24 and IOW56 we need a buffer */
347 	struct urb *int_out_urb = NULL;
348 
349 	dev = (struct iowarrior *)file->private_data;
350 
351 	mutex_lock(&dev->mutex);
352 	/* verify that the device wasn't unplugged */
353 	if (dev == NULL || !dev->present) {
354 		retval = -ENODEV;
355 		goto exit;
356 	}
357 	dbg("%s - minor %d, count = %zd", __func__, dev->minor, count);
358 	/* if count is 0 we're already done */
359 	if (count == 0) {
360 		retval = 0;
361 		goto exit;
362 	}
363 	/* We only accept full reports */
364 	if (count != dev->report_size) {
365 		retval = -EINVAL;
366 		goto exit;
367 	}
368 	switch (dev->product_id) {
369 	case USB_DEVICE_ID_CODEMERCS_IOW24:
370 	case USB_DEVICE_ID_CODEMERCS_IOWPV1:
371 	case USB_DEVICE_ID_CODEMERCS_IOWPV2:
372 	case USB_DEVICE_ID_CODEMERCS_IOW40:
373 		/* IOW24 and IOW40 use a synchronous call */
374 		buf = kmalloc(8, GFP_KERNEL);	/* 8 bytes are enough for both products */
375 		if (!buf) {
376 			retval = -ENOMEM;
377 			goto exit;
378 		}
379 		if (copy_from_user(buf, user_buffer, count)) {
380 			retval = -EFAULT;
381 			kfree(buf);
382 			goto exit;
383 		}
384 		retval = usb_set_report(dev->interface, 2, 0, buf, count);
385 		kfree(buf);
386 		goto exit;
387 		break;
388 	case USB_DEVICE_ID_CODEMERCS_IOW56:
389 		/* The IOW56 uses asynchronous IO and more urbs */
390 		if (atomic_read(&dev->write_busy) == MAX_WRITES_IN_FLIGHT) {
391 			/* Wait until we are below the limit for submitted urbs */
392 			if (file->f_flags & O_NONBLOCK) {
393 				retval = -EAGAIN;
394 				goto exit;
395 			} else {
396 				retval = wait_event_interruptible(dev->write_wait,
397 								  (!dev->present || (atomic_read (&dev-> write_busy) < MAX_WRITES_IN_FLIGHT)));
398 				if (retval) {
399 					/* we were interrupted by a signal */
400 					retval = -ERESTART;
401 					goto exit;
402 				}
403 				if (!dev->present) {
404 					/* The device was unplugged */
405 					retval = -ENODEV;
406 					goto exit;
407 				}
408 				if (!dev->opened) {
409 					/* We were closed while waiting for an URB */
410 					retval = -ENODEV;
411 					goto exit;
412 				}
413 			}
414 		}
415 		atomic_inc(&dev->write_busy);
416 		int_out_urb = usb_alloc_urb(0, GFP_KERNEL);
417 		if (!int_out_urb) {
418 			retval = -ENOMEM;
419 			dbg("%s Unable to allocate urb ", __func__);
420 			goto error;
421 		}
422 		buf = usb_buffer_alloc(dev->udev, dev->report_size,
423 				       GFP_KERNEL, &int_out_urb->transfer_dma);
424 		if (!buf) {
425 			retval = -ENOMEM;
426 			dbg("%s Unable to allocate buffer ", __func__);
427 			goto error;
428 		}
429 		usb_fill_int_urb(int_out_urb, dev->udev,
430 				 usb_sndintpipe(dev->udev,
431 						dev->int_out_endpoint->bEndpointAddress),
432 				 buf, dev->report_size,
433 				 iowarrior_write_callback, dev,
434 				 dev->int_out_endpoint->bInterval);
435 		int_out_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
436 		if (copy_from_user(buf, user_buffer, count)) {
437 			retval = -EFAULT;
438 			goto error;
439 		}
440 		retval = usb_submit_urb(int_out_urb, GFP_KERNEL);
441 		if (retval) {
442 			dbg("%s submit error %d for urb nr.%d", __func__,
443 			    retval, atomic_read(&dev->write_busy));
444 			goto error;
445 		}
446 		/* submit was ok */
447 		retval = count;
448 		usb_free_urb(int_out_urb);
449 		goto exit;
450 		break;
451 	default:
452 		/* what do we have here ? An unsupported Product-ID ? */
453 		dev_err(&dev->interface->dev, "%s - not supported for product=0x%x",
454 			__FUNCTION__, dev->product_id);
455 		retval = -EFAULT;
456 		goto exit;
457 		break;
458 	}
459 error:
460 	usb_buffer_free(dev->udev, dev->report_size, buf,
461 			int_out_urb->transfer_dma);
462 	usb_free_urb(int_out_urb);
463 	atomic_dec(&dev->write_busy);
464 	wake_up_interruptible(&dev->write_wait);
465 exit:
466 	mutex_unlock(&dev->mutex);
467 	return retval;
468 }
469 
470 /**
471  *	iowarrior_ioctl
472  */
473 static int iowarrior_ioctl(struct inode *inode, struct file *file,
474 			   unsigned int cmd, unsigned long arg)
475 {
476 	struct iowarrior *dev = NULL;
477 	__u8 *buffer;
478 	__u8 __user *user_buffer;
479 	int retval;
480 	int io_res;		/* checks for bytes read/written and copy_to/from_user results */
481 
482 	dev = (struct iowarrior *)file->private_data;
483 	if (dev == NULL) {
484 		return -ENODEV;
485 	}
486 
487 	buffer = kzalloc(dev->report_size, GFP_KERNEL);
488 	if (!buffer)
489 		return -ENOMEM;
490 
491 	/* lock this object */
492 	mutex_lock(&dev->mutex);
493 
494 	/* verify that the device wasn't unplugged */
495 	if (!dev->present) {
496 		mutex_unlock(&dev->mutex);
497 		return -ENODEV;
498 	}
499 
500 	dbg("%s - minor %d, cmd 0x%.4x, arg %ld", __func__, dev->minor, cmd,
501 	    arg);
502 
503 	retval = 0;
504 	io_res = 0;
505 	switch (cmd) {
506 	case IOW_WRITE:
507 		if (dev->product_id == USB_DEVICE_ID_CODEMERCS_IOW24 ||
508 		    dev->product_id == USB_DEVICE_ID_CODEMERCS_IOWPV1 ||
509 		    dev->product_id == USB_DEVICE_ID_CODEMERCS_IOWPV2 ||
510 		    dev->product_id == USB_DEVICE_ID_CODEMERCS_IOW40) {
511 			user_buffer = (__u8 __user *)arg;
512 			io_res = copy_from_user(buffer, user_buffer,
513 						dev->report_size);
514 			if (io_res) {
515 				retval = -EFAULT;
516 			} else {
517 				io_res = usb_set_report(dev->interface, 2, 0,
518 							buffer,
519 							dev->report_size);
520 				if (io_res < 0)
521 					retval = io_res;
522 			}
523 		} else {
524 			retval = -EINVAL;
525 			dev_err(&dev->interface->dev,
526 				"ioctl 'IOW_WRITE' is not supported for product=0x%x.",
527 				dev->product_id);
528 		}
529 		break;
530 	case IOW_READ:
531 		user_buffer = (__u8 __user *)arg;
532 		io_res = usb_get_report(dev->udev,
533 					dev->interface->cur_altsetting, 1, 0,
534 					buffer, dev->report_size);
535 		if (io_res < 0)
536 			retval = io_res;
537 		else {
538 			io_res = copy_to_user(user_buffer, buffer, dev->report_size);
539 			if (io_res < 0)
540 				retval = -EFAULT;
541 		}
542 		break;
543 	case IOW_GETINFO:
544 		{
545 			/* Report available information for the device */
546 			struct iowarrior_info info;
547 			/* needed for power consumption */
548 			struct usb_config_descriptor *cfg_descriptor = &dev->udev->actconfig->desc;
549 
550 			/* directly from the descriptor */
551 			info.vendor = le16_to_cpu(dev->udev->descriptor.idVendor);
552 			info.product = dev->product_id;
553 			info.revision = le16_to_cpu(dev->udev->descriptor.bcdDevice);
554 
555 			/* 0==UNKNOWN, 1==LOW(usb1.1) ,2=FULL(usb1.1), 3=HIGH(usb2.0) */
556 			info.speed = le16_to_cpu(dev->udev->speed);
557 			info.if_num = dev->interface->cur_altsetting->desc.bInterfaceNumber;
558 			info.report_size = dev->report_size;
559 
560 			/* serial number string has been read earlier 8 chars or empty string */
561 			memcpy(info.serial, dev->chip_serial,
562 			       sizeof(dev->chip_serial));
563 			if (cfg_descriptor == NULL) {
564 				info.power = -1;	/* no information available */
565 			} else {
566 				/* the MaxPower is stored in units of 2mA to make it fit into a byte-value */
567 				info.power = cfg_descriptor->bMaxPower * 2;
568 			}
569 			io_res = copy_to_user((struct iowarrior_info __user *)arg, &info,
570 					 sizeof(struct iowarrior_info));
571 			if (io_res < 0)
572 				retval = -EFAULT;
573 			break;
574 		}
575 	default:
576 		/* return that we did not understand this ioctl call */
577 		retval = -ENOTTY;
578 		break;
579 	}
580 
581 	/* unlock the device */
582 	mutex_unlock(&dev->mutex);
583 	return retval;
584 }
585 
586 /**
587  *	iowarrior_open
588  */
589 static int iowarrior_open(struct inode *inode, struct file *file)
590 {
591 	struct iowarrior *dev = NULL;
592 	struct usb_interface *interface;
593 	int subminor;
594 	int retval = 0;
595 
596 	dbg("%s", __func__);
597 
598 	subminor = iminor(inode);
599 
600 	/* prevent disconnects */
601 	down(&disconnect_sem);
602 
603 	interface = usb_find_interface(&iowarrior_driver, subminor);
604 	if (!interface) {
605 		err("%s - error, can't find device for minor %d", __FUNCTION__,
606 		    subminor);
607 		retval = -ENODEV;
608 		goto out;
609 	}
610 
611 	dev = usb_get_intfdata(interface);
612 	if (!dev) {
613 		retval = -ENODEV;
614 		goto out;
615 	}
616 
617 	/* Only one process can open each device, no sharing. */
618 	if (dev->opened) {
619 		retval = -EBUSY;
620 		goto out;
621 	}
622 
623 	/* setup interrupt handler for receiving values */
624 	if ((retval = usb_submit_urb(dev->int_in_urb, GFP_KERNEL)) < 0) {
625 		dev_err(&interface->dev, "Error %d while submitting URB\n", retval);
626 		retval = -EFAULT;
627 		goto out;
628 	}
629 	/* increment our usage count for the driver */
630 	++dev->opened;
631 	/* save our object in the file's private structure */
632 	file->private_data = dev;
633 	retval = 0;
634 
635 out:
636 	up(&disconnect_sem);
637 	return retval;
638 }
639 
640 /**
641  *	iowarrior_release
642  */
643 static int iowarrior_release(struct inode *inode, struct file *file)
644 {
645 	struct iowarrior *dev;
646 	int retval = 0;
647 
648 	dev = (struct iowarrior *)file->private_data;
649 	if (dev == NULL) {
650 		return -ENODEV;
651 	}
652 
653 	dbg("%s - minor %d", __func__, dev->minor);
654 
655 	/* lock our device */
656 	mutex_lock(&dev->mutex);
657 
658 	if (dev->opened <= 0) {
659 		retval = -ENODEV;	/* close called more than once */
660 		mutex_unlock(&dev->mutex);
661 	} else {
662 		dev->opened = 0;	/* we're closeing now */
663 		retval = 0;
664 		if (dev->present) {
665 			/*
666 			   The device is still connected so we only shutdown
667 			   pending read-/write-ops.
668 			 */
669 			usb_kill_urb(dev->int_in_urb);
670 			wake_up_interruptible(&dev->read_wait);
671 			wake_up_interruptible(&dev->write_wait);
672 			mutex_unlock(&dev->mutex);
673 		} else {
674 			/* The device was unplugged, cleanup resources */
675 			mutex_unlock(&dev->mutex);
676 			iowarrior_delete(dev);
677 		}
678 	}
679 	return retval;
680 }
681 
682 static unsigned iowarrior_poll(struct file *file, poll_table * wait)
683 {
684 	struct iowarrior *dev = file->private_data;
685 	unsigned int mask = 0;
686 
687 	if (!dev->present)
688 		return POLLERR | POLLHUP;
689 
690 	poll_wait(file, &dev->read_wait, wait);
691 	poll_wait(file, &dev->write_wait, wait);
692 
693 	if (!dev->present)
694 		return POLLERR | POLLHUP;
695 
696 	if (read_index(dev) != -1)
697 		mask |= POLLIN | POLLRDNORM;
698 
699 	if (atomic_read(&dev->write_busy) < MAX_WRITES_IN_FLIGHT)
700 		mask |= POLLOUT | POLLWRNORM;
701 	return mask;
702 }
703 
704 /*
705  * File operations needed when we register this driver.
706  * This assumes that this driver NEEDS file operations,
707  * of course, which means that the driver is expected
708  * to have a node in the /dev directory. If the USB
709  * device were for a network interface then the driver
710  * would use "struct net_driver" instead, and a serial
711  * device would use "struct tty_driver".
712  */
713 static struct file_operations iowarrior_fops = {
714 	.owner = THIS_MODULE,
715 	.write = iowarrior_write,
716 	.read = iowarrior_read,
717 	.ioctl = iowarrior_ioctl,
718 	.open = iowarrior_open,
719 	.release = iowarrior_release,
720 	.poll = iowarrior_poll,
721 };
722 
723 /*
724  * usb class driver info in order to get a minor number from the usb core,
725  * and to have the device registered with devfs and the driver core
726  */
727 static struct usb_class_driver iowarrior_class = {
728 	.name = "iowarrior%d",
729 	.fops = &iowarrior_fops,
730 	.minor_base = IOWARRIOR_MINOR_BASE,
731 };
732 
733 /*---------------------------------*/
734 /*  probe and disconnect functions */
735 /*---------------------------------*/
736 /**
737  *	iowarrior_probe
738  *
739  *	Called by the usb core when a new device is connected that it thinks
740  *	this driver might be interested in.
741  */
742 static int iowarrior_probe(struct usb_interface *interface,
743 			   const struct usb_device_id *id)
744 {
745 	struct usb_device *udev = interface_to_usbdev(interface);
746 	struct iowarrior *dev = NULL;
747 	struct usb_host_interface *iface_desc;
748 	struct usb_endpoint_descriptor *endpoint;
749 	int i;
750 	int retval = -ENOMEM;
751 	int idele = 0;
752 
753 	/* allocate memory for our device state and intialize it */
754 	dev = kzalloc(sizeof(struct iowarrior), GFP_KERNEL);
755 	if (dev == NULL) {
756 		dev_err(&interface->dev, "Out of memory");
757 		return retval;
758 	}
759 
760 	mutex_init(&dev->mutex);
761 
762 	atomic_set(&dev->intr_idx, 0);
763 	atomic_set(&dev->read_idx, 0);
764 	spin_lock_init(&dev->intr_idx_lock);
765 	atomic_set(&dev->overflow_flag, 0);
766 	init_waitqueue_head(&dev->read_wait);
767 	atomic_set(&dev->write_busy, 0);
768 	init_waitqueue_head(&dev->write_wait);
769 
770 	dev->udev = udev;
771 	dev->interface = interface;
772 
773 	iface_desc = interface->cur_altsetting;
774 	dev->product_id = le16_to_cpu(udev->descriptor.idProduct);
775 
776 	/* set up the endpoint information */
777 	for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
778 		endpoint = &iface_desc->endpoint[i].desc;
779 
780 		if (usb_endpoint_is_int_in(endpoint))
781 			dev->int_in_endpoint = endpoint;
782 		if (usb_endpoint_is_int_out(endpoint))
783 			/* this one will match for the IOWarrior56 only */
784 			dev->int_out_endpoint = endpoint;
785 	}
786 	/* we have to check the report_size often, so remember it in the endianess suitable for our machine */
787 	dev->report_size = le16_to_cpu(dev->int_in_endpoint->wMaxPacketSize);
788 	if ((dev->interface->cur_altsetting->desc.bInterfaceNumber == 0) &&
789 	    (dev->product_id == USB_DEVICE_ID_CODEMERCS_IOW56))
790 		/* IOWarrior56 has wMaxPacketSize different from report size */
791 		dev->report_size = 7;
792 
793 	/* create the urb and buffer for reading */
794 	dev->int_in_urb = usb_alloc_urb(0, GFP_KERNEL);
795 	if (!dev->int_in_urb) {
796 		dev_err(&interface->dev, "Couldn't allocate interrupt_in_urb\n");
797 		goto error;
798 	}
799 	dev->int_in_buffer = kmalloc(dev->report_size, GFP_KERNEL);
800 	if (!dev->int_in_buffer) {
801 		dev_err(&interface->dev, "Couldn't allocate int_in_buffer\n");
802 		goto error;
803 	}
804 	usb_fill_int_urb(dev->int_in_urb, dev->udev,
805 			 usb_rcvintpipe(dev->udev,
806 					dev->int_in_endpoint->bEndpointAddress),
807 			 dev->int_in_buffer, dev->report_size,
808 			 iowarrior_callback, dev,
809 			 dev->int_in_endpoint->bInterval);
810 	/* create an internal buffer for interrupt data from the device */
811 	dev->read_queue =
812 	    kmalloc(((dev->report_size + 1) * MAX_INTERRUPT_BUFFER),
813 		    GFP_KERNEL);
814 	if (!dev->read_queue) {
815 		dev_err(&interface->dev, "Couldn't allocate read_queue\n");
816 		goto error;
817 	}
818 	/* Get the serial-number of the chip */
819 	memset(dev->chip_serial, 0x00, sizeof(dev->chip_serial));
820 	usb_string(udev, udev->descriptor.iSerialNumber, dev->chip_serial,
821 		   sizeof(dev->chip_serial));
822 	if (strlen(dev->chip_serial) != 8)
823 		memset(dev->chip_serial, 0x00, sizeof(dev->chip_serial));
824 
825 	/* Set the idle timeout to 0, if this is interface 0 */
826 	if (dev->interface->cur_altsetting->desc.bInterfaceNumber == 0) {
827 		idele = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
828 					0x0A,
829 					USB_TYPE_CLASS | USB_RECIP_INTERFACE, 0,
830 					0, NULL, 0, USB_CTRL_SET_TIMEOUT);
831 		dbg("idele = %d", idele);
832 	}
833 	/* allow device read and ioctl */
834 	dev->present = 1;
835 
836 	/* we can register the device now, as it is ready */
837 	usb_set_intfdata(interface, dev);
838 
839 	retval = usb_register_dev(interface, &iowarrior_class);
840 	if (retval) {
841 		/* something prevented us from registering this driver */
842 		dev_err(&interface->dev, "Not able to get a minor for this device.\n");
843 		usb_set_intfdata(interface, NULL);
844 		goto error;
845 	}
846 
847 	dev->minor = interface->minor;
848 
849 	/* let the user know what node this device is now attached to */
850 	dev_info(&interface->dev, "IOWarrior product=0x%x, serial=%s interface=%d "
851 		 "now attached to iowarrior%d\n", dev->product_id, dev->chip_serial,
852 		 iface_desc->desc.bInterfaceNumber, dev->minor - IOWARRIOR_MINOR_BASE);
853 	return retval;
854 
855 error:
856 	iowarrior_delete(dev);
857 	return retval;
858 }
859 
860 /**
861  *	iowarrior_disconnect
862  *
863  *	Called by the usb core when the device is removed from the system.
864  */
865 static void iowarrior_disconnect(struct usb_interface *interface)
866 {
867 	struct iowarrior *dev;
868 	int minor;
869 
870 	/* prevent races with open() */
871 	down(&disconnect_sem);
872 
873 	dev = usb_get_intfdata(interface);
874 	usb_set_intfdata(interface, NULL);
875 
876 	mutex_lock(&dev->mutex);
877 
878 	minor = dev->minor;
879 
880 	/* give back our minor */
881 	usb_deregister_dev(interface, &iowarrior_class);
882 
883 	/* prevent device read, write and ioctl */
884 	dev->present = 0;
885 
886 	mutex_unlock(&dev->mutex);
887 
888 	if (dev->opened) {
889 		/* There is a process that holds a filedescriptor to the device ,
890 		   so we only shutdown read-/write-ops going on.
891 		   Deleting the device is postponed until close() was called.
892 		 */
893 		usb_kill_urb(dev->int_in_urb);
894 		wake_up_interruptible(&dev->read_wait);
895 		wake_up_interruptible(&dev->write_wait);
896 	} else {
897 		/* no process is using the device, cleanup now */
898 		iowarrior_delete(dev);
899 	}
900 	up(&disconnect_sem);
901 
902 	dev_info(&interface->dev, "I/O-Warror #%d now disconnected\n",
903 		 minor - IOWARRIOR_MINOR_BASE);
904 }
905 
906 /* usb specific object needed to register this driver with the usb subsystem */
907 static struct usb_driver iowarrior_driver = {
908 	.name = "iowarrior",
909 	.probe = iowarrior_probe,
910 	.disconnect = iowarrior_disconnect,
911 	.id_table = iowarrior_ids,
912 };
913 
914 static int __init iowarrior_init(void)
915 {
916 	return usb_register(&iowarrior_driver);
917 }
918 
919 static void __exit iowarrior_exit(void)
920 {
921 	usb_deregister(&iowarrior_driver);
922 }
923 
924 module_init(iowarrior_init);
925 module_exit(iowarrior_exit);
926